MELBOURNE, Australia (AP):Nearly a week into the Australian Open, the only major surprise is that there have been, well, not many surprises at all.

The year's first Grand Slam is historically fraught with injury withdrawals or top players not yet up to speed in the new season and losing in the first few rounds.

But with the third round complete for the leading players at Melbourne Park, only one of the first eight men's seeds did not advance - No. 6 Juan Martin del Potro. Six of the eight top women were through.

Second-seeded Roger Federer was the last of the main contenders to advance to the fourth round, beating Australian Bernard Tomic 6-4, 7-6 (5), 6-1. Federer trailed 4-1 in the tiebreaker but rallied for six of the next seven points in front of a full house at the 15,000-seat Rod Laver Arena.

"I had a few more chances than he did, but I thought the tiebreaker was going to go his way," said Federer. "I think overall we played a great match, he really got the best out of me tonight."

The four-time Australian Open champion will next play big-serving Canadian Milos Raonic, who beat No. 17 Philipp Kohlschreiber of Germany 7-6 (4), 6-3, 6-4.

Del Potro was a 6-3, 6-3, 6-7 (3), 3-6, 6-3 loser to France's Jeremy Chardy earlier yesterday in the biggest upset so far in this tournament.

Those still around have advanced fairly impressively.

Top-seeded Novak Djokovic and No. 3 Andy Murray haven't dropped a set in three matches, although Murray had his difficult moments in Saturday's 6-3, 6-4, 7-5 win over Lithuanian qualifier and sometimes hitting partner Ricardas Berankis, while fourth-seeded David Ferrer has lost just one set.

Simon advanced with a 6-4, 6-4, 4-6, 1-6, 8-6 win over fellow Frenchman Gael Monfils in a 4-hour, 39-minute match that ended at 12:32 a.m. local time Sunday morning, concluding the third round.

Seventh-seeded Jo-Wilfried Tsonga beat Slovenian Blaz Kavcic 6-2, 6-1, 6-4 and will meet countryman Richard Gasquet, who beat Croatian Ivan Dodig 4-6, 6-3, 7-6 (2), 6-0.

Andrea Seppi of Italy beat Croatia's Marin Cilic 6-7 (2), 6-3, 2-6, 6-4, 6-2 to also advance to the fourth round.

In women's play, top-seeded Victoria Azarenka had her problems against injury-affected American Jamie Hampton and needed three sets to advance but No. 3 Serena Williams has not dropped a set despite an injured right ankle.

"There's always two ways - your opponent plays good and you can also make your opponent look good," Azarenka said after her 6-4, 4-6. 6-2 win.

Williams, aiming for a third consecutive major title, recovered from a breakdown in the second set to win six straight games and beat Japan's Ayumi Morita 6-1, 6-3. She later combined with older sister Venus to win a second-round doubles match.

The other half of the women's draw, which didn't play yesterday is more impressive: No. 2 Maria Sharapova dropped only four games in three rounds - including consecutive 6-0, 6-0 wins to start her tournament, while No. 4 Agnieszka Radwanska is on a 12-match winning streak after capturing tournaments in Auckland and Sydney ahead of her three wins here.